In the magnetic recording field, the amount of information to be transacted has increased in computer systems and other recording media. It therefore is desired to increase recording data density. To satisfy this demand high magnetic permeability and high saturation magnetic flux density are required for magnetic head core materials. A magnetic head core is also required to have high wear resistance and corrosion resistance.
It is known that a Sendust alloy consisting of silicon of 9.5 wt%, aluminum of 5.5 wt% and the rest of iron exhibits high magnetic permeability and high saturation magnetic flux density. The Sendust alloy also has high hardness, i.e. a Vickers hardness of 450 to 500, and has high wear resistance. Accordingly it is highly used for magnetic heads in Video Tape recording systems for broadcasting, because the magnetic head is employed under a higher relative velocity to the recording tapes. Even a Sendust alloy having such a high wear resistance exhibits defects in particular conditions, such as where a tape having a high degree of abrasion is employed or where the head is used in humid air.
It has been found by the present inventors that the aforesaid defects, especially abrasion in a moist atmosphere, is brought about by both chemical reaction and mechanical defacement occurring between a magnetic head and a magnetic tape in some cases. It is strongly desired that a Sendust alloy possess not only high magnetic permeability and high saturation magnetic flux density but also possess high wear resistance and corrosion resistance.